Nonskid tire



Patented Oct. 21, 1941 7 2,260,193 NONSKID TIRE 'Max 0. Overman, New York, N. Y., assignor, by mesne assignments, to M. C. 0. Corporation, New York, N. Y., a, corporation of Delaware Application September 17, 193 Serial No. 230,355

8 Claims.

This invention relates to tires and aims to provide an improved non-skid tire.

In my c-pending application Serial No. 221,060, filed July 25, 1938, I have shown and described several modifications of a tire tread comprising generally circumferential load bearing ribs including straight and more or less serpentine circumferentially extending ribs. As

' shown in Figure 4 of that application short noncontinuous load supporting tread areas are provided at intervals between adjoining straight and serpentine continuous load supporting ribs in order to compensate for the difference in contour between the straight ribs and the serpentine ribs.

I have found that certain disadvantages arise from combining tread surfaces of different sizes and area. In general, other factors being equal, larger masses of tread surface will wear more rapidly than smaller masses due to the fact that they are less flexible and therefore subject to "greater friction. On the other hand small masses tend to develop heel and toe wear, 1, e., the front and rear edges of the mass become worn more rapidly than the middle or central portion.

, My present invention relates to an improved tread structure combining continuous straight and serpentine load supporting ribs in such a way as to eliminate the short non-continuous load supporting tread areas, and to minimize differences in mass of the load supporting areas, particularly in the central portion of the tread which is subjected to the greatest wear.v In

carrying out my invention I provide a tread surface comprising one or more circumferential straight load supporting ribs and a number of circumferentially extending serpentine load supporting ribs, and compensate for the difference in contour between the straight and serpentine ribs by increasing the width of portions of the load bearing ribs or of the spaces or grooves between the load bearing ribs, or both,v prefer.- ably progressively in both directions from the medianline of the tire. Extending upwardly from the bottom of the respective grooves I provide other ribs narrower than the load supporting ribs and each narrower than the groove in which it is formed but corresponding to it in contour.

ribs the safety qualities of the tire are increased and I58, and IE1 and I (is, are provided.

in proportion to the distortion of the tread, the ribs with the greatest curvature being functionally employed when the need for them is greatest.

It will be understood that the modification of the invention as described herein is presented by way of explanation and not of limitation, and that the number, size, and curvature of the load bearing ribs, intermediate grooves, and the reinforcing ribs, may be substantially varied according to the purpose for which the tire is designed, without departing from the scope of the invention. 7

.My invention Will best be understood if the following description is read in connection with the drawing, in which:

Figure 1 is a top plan view of. a portion of the tread surface; and

Figure 2 is a transverse sectional viewof the tread portion of atire.

In the modification of the invention illustrated in the drawing a straight loadsupporting rib I0 is shown extending around the median or central portion of the tire. On either side of the straight ribv I0 and adjacent theretoare the serpentine ribs Ila and II?) respectively, and beyond the ribs Ila and III) are the ribs 12a and I2b of somewhat greater curvature than ribs Ila and Nb. Beyond the ribs I2a and I2!) are ribs [3a and I3b which extend into the side walls of the tire and normally are called upon to support very little'of the load.

Between load supporting rib I 0 and load supporting. ribs .IIaand IIb respectively are ;the grooves Ma and Nb; between the load supporting ribs Na and Ilb and Hit and I2!) respectively are the grooves -I5a and I51 and between the ribs IZa and IZb and I3a and I3b respec- 'tivelyare the grooves I61: and I61). In the respecti e grooves reinforcing ribs I4? and Ms, I51

They are narrower than ribs'It, Ila,- II'b, I20, and I2!) and are normally non-load supporting. They serve to reinforcethe load supporting ribs when the latter are distorted.v Each of the reinforcing ribs is spaced somewhat fromthe side walls of] the adjoining loadsupporting ribs when the latter are, not .distortedand follows the contour of the groove in which it is located. The

reinforcing r'ibs may be made shorter than the is intended.

Preferably both the load supporting ribs and thereinforcing ribs are formed withnon-draft side walls, i. e. side walls which are normal to the tread surface.

It will be seen thatgrooves Ma and i th, and |a and. l5b, have portions, Fla and Nb, and l-Ba and |8bj respectively, of increased width in alinement with the outwardly curving portions 19a and 20a, and I91) and 20b, of the load support; ing ribs on their respective sides of the median rib H3. It will also be seen that portionspfthe ff to *the extent ,to which the most serpentine ribs,

:ljZa and I217, deviate from .a straight line. In

. 'this 'Way non-continuous load supporting tread areas :are eliminatedan'd themassesoi the supporting ribs are'made to app oach equality.

' ,jThe ribs 12a and ,I2b,;being themost serpentine are therefore of high tractive qualities.

"Most of the load will ordinarily be-supported by the greatest degree of curvature are spaced furthest from the median line of the tire to give increased traction under increased loads.

4. A non-skid tire having a tread comprising a number of spaced serpentine load bearing ribs of .fdififering curvature having sides normal to the tread surface and distortable under lateral stress arranged so that the ribs with the lesser curva- ,;tureare-;positioned in the portion of the tread normally .in contact with a hard road surface whereas the ribs-with the greater curvature are straight 'rib H3 and moderately curved serpentine -ribs 'I la and Nb, but in sandor mud,.0rupon sudden distortion of ,the jtr ead'as under severe deceleration or acceleration; the,ribs In and l2b 'vvilLcomeinto full play The improved structure disclosed herein is adapted to give a high degree of traction without the digging which is characteristic of transverse pleats, and which insoft ground'tends to dig holes under the tires.

The depth qithegrooves or spaces between the fload supportingj ribs ,may be varied widely .de-

pending on the type, intended use and ,characteristics jdesiredof the tire. 'While the .inv e1 '1tionyisnot' limited to any dimensions, grooves of'adepth of from 'threeeighths to one half an inch are preferred for average passenger ,car

tires. For special'uses, .for example ,in tractor tires, 1 it may be desira le to mate ally in the depth ofthe grooves.

a I l m s; A. 1. Anon-skid tire having a treadportioncomprising aistraight load bearing rib extending vcircumferential-1y around the median line of thetire and serpentine ribs of differing curvature arranged on either side of said straight rib in a 'mannersuch that the degree of curvature of said serpentine ribs'increases progressively in proportion to the distance from the straight median rib.

2. Anon-skid tire having a tread portion com- .prising -a straight load bearing rib extending ,Circumferentially around the median line of "the tire and serpentine -ribs of difiering=curvature arranged at spaced intervals on either side of saidstraight ,rib ,in .a mannersuch that the degree of. curvature 'o f said serpentine ribs increases progressively in proportion to the dis,- tancei from the straight median rib; and circumferent ially extending non-load bearing serpentine ribs of jncmuniform "width extending outwardly fromthebottomof the spaces between said. load bearing-ribs, thecurvature of saidnon-load bearing ribs" also increasing progressively in proportionitothe distance from the straight median Tib- V Y r j 3. A nonskid tire having a tread comprising two groups --of serpentine load bearing --ribs of difiering: curvature arranged soth-at the ribswith positioned vbetween the aforesaid ribs and the. side Walls of the tire.

5; Anon-skid tire having a straight load bearing ,rib extending circumferentially around the median line of the tread, and serpentine load bearing ,ribs, increasing respectively in-v curvature ,p ffigressively in proportion toItheir-distancef-rom said straight rib, spaced from one another by spaces having .portions .of increased width proportional to the undulations of said serpentine ribs. 7 g.

6. Anon-skid tire having a straight loadbearing' rib extending aroundthe median line of -the tire, serpentine load bearing .ribs disposed-on either side of said straightvload bearing- -=rib,. and narrow, serpentine, substantially non-load .bearing ribs disposed alternately .with said load bearing ribs in the spaces between said load bearing ribs butspacedfrom the side walls oilsaid load bearing ribs by spacesnarrower than the width .of said substantially non-load bearing ribs said serpentine load bearing ribs being of different curvatures, each successive rib, from themedian rib orribs outwardly, becoming more :undulant than the Wnextadj'oining rib between it and the medianrrib or ribssaid non-.load .bearingribs having portionsof increased .width proportional .tothe difierence in-thecurvature of the gadjacent sides of'adjoining load bearing ribs.

'7. A non-skid tire-having atread portionicomprising a high, straight, load bearing.rib,.extending circumferentially around the median line-of the tire, seirpehtineload bearing ribs dispQsed;on either. side .of said straight. central 1%, "each qf said load bearing ribs having parallel sides rand being of greater .width then.height,- and narrower {substantially non-load bearing ribs, disposed alternately with .said load bearing ..ribs, said s ub-- .stantially non-load bearing .ribs .beingrofgreater h ig t anwidtnand spacedon. both. sides hem said loadbearing ribs. 7 l 1 l 8. A non-skid ,tire comprising -:alte1;nate ly -,a

numbenof circumferentially. extendingloadbear.-

jng ribs, and. narrow, substantially; non-load;

bearing ribs Qf .greaterheight than .width, --,all of said load bearing .and substantially non load bearing .ribs having substantially parallel side I walls, the non-load bearing vribs beingspaced curriferentially'iarqundthe'median line.of thetire, a and said other load. bearing. ribs being serpentine '3 oining serp'entine ribs.

frornthe load bearing .ribsby spaces which-are only a fraction of ,the. width.of thesubstantially non-load bearing ribs, at least one .of-said load.

bearing ribs bein a. straight rib extending-,-

' MAX e. *ovERMAN. 

